It is well-known to provide an ore crusher in a rectangular, box-shaped embedded housing of reinforced concrete. This permits heavy haul ore trucks to dump their contents into a hole in the ground to eliminate the need for elevating the uncrushed ore to a height which would require considerable work to do so. the rectangular configuration of such a housing requires that a considerable amount of concrete and reinforcing steel be used to render the housing structurally sound but yet large enough to house not only the crusher itself but also other equipment and chambers, such as an elevator, a surge pocket, a conveyor, drive machinery and the like. Moreover, in the construction of a rectangular housing of conventional design, considerable expense is always encountered in the placement of the large amount of reinforcing steel that is required. Also, a problem exists in properly pouring concrete around the closely spaced reinforcing steel to form the rectangular wall of the housing.
An attempt to reduce the amount of concrete and reinforcing steel in housing of this type has resulted in the development of a housing having a single circular shape, such as a standard silo shape. This shape, when considered from a structural point of view, offers great promise because the exterior wall of concrete is stressed in its most efficient manner, i.e., as a closed ring in compression. Such a structure has an ability to resist the very high lateral pressures resulting from earth backfill as well as the surcharge from heavy haul trucks. The single circle configuration offers a significant savings in materials when compared with the heavy slab-beam-strut concept used in the conventional rectangular crusher housing and the massive use of concrete and reinforcing steel of such rectangular housing. These savings result from a reduction of average exterior wall thickness of three to four feet as required by the rectangular structure to a minimum of eighteen to twenty-four inches for the single circular configuration. In addition, significant savings in reinforcing steel are achieved due to the concept of carrying principal loads by concrete in compression instead of bending in heavy slabs.
While the single circular shape of pressure housing has certain advantages, it does not provide for the optimum use of the space therein. This drawback requires that the single circular housing be relatively large in size, thereby requiring large amounts of concrete and reinforcing steel although such amounts are less than those required in the conventional rectangular housings.
Because of the foregoing, a need has arisen for an improved underground crusher housing which utilizes the structural features of the single circular configuration of housing yet further minimizes the concrete and reinforcing steel required to provide a structurally sound housing yet provide for adequate space to contain all of the necessary equipment to carry out ore crushing operation.